Maq's low-tech troubles

[_Maq_]

induces a slight deficiency if the very lean dosing regime isn’t increased to compensate, leading some release of organics from the leaves and a resulting foothold for algae?

Possibly, but at this moment, I can't recall reading a scientific paper which suggested that nutrient deficiency leads to increased organics exudation from leaves. Roots... yes, that's possible, even likely in some cases.

Yesterday, I measured pH in all tanks again. While three of them remain higher than I'd like (even slightly above 7), the fourth returned pH = 5.06. What could be the cause of such a sudden drop? I can't think of anything else but nitrification. It looks like nitrification has got somehow hindered during temperature increase, and now it works again. (I should add that to provoke pH drop by nitrification I've dosed nitrogen only in ammoniacal form.)
If we permit that temperature increase can temporarily hinder nitrification, it may have important ramifications.
And what might have caused that nitrification collapse/decrease? I'm thinking about sudden increase in numbers/activity of heterotrophic microbes. These outcompete nitrifying microbes, and it takes time before the latter adapt.

Whatever the exact mechanism, I've observed that temperature increase has changed the balance of 'invisible factors' (microbial community) in my tanks and has led to unwanted incidents.

 

[Wookii]

Possibly, but at this moment, I can't recall reading a scientific paper which suggested that nutrient deficiency leads to increased organics exudation from leaves. Roots... yes, that's possible, even likely in some cases.

OK, whatever the exact mechanism, it is often seen that weakening plants leaves will be a magnet for algae forming where healthy leaves aren't - that is what I was referring to.

Yesterday, I measured pH in all tanks again. While three of them remain higher than I'd like (even slightly above 7), the fourth returned pH = 5.06. What could be the cause of such a sudden drop? I can't think of anything else but nitrification. It looks like nitrification has got somehow hindered during temperature increase, and now it works again.

That is a large change in pH! Could it be related to the reduced DO levels in warmer water affecting the microbial colony?

 

[_Maq_]

Could it be related to the reduced DO levels in warmer water affecting the microbial colony?

I think yes, but the prime factor is the temperature itself. There's a general rule that microbes double their activity with 10° increase in temperature. Many - if not most - of the heterotrophic bacteria can switch to respiring nitrates or iron when oxygen is in scarce supply, while nitrifying microbes can't. It suggests that many niches where nitrifiers lived happily before became suboxic, and therefore the drop in nitrification.

This is a counter-argument to my practice of not using any biofiltration. If some of the nitrifiers lived in a filter with improved availability of oxygen, maybe the negative effects would be less pronounced. But who knows?

 

[LMuhlen]

You mention a temperature increase from 19 to 25°C. Your high range is my low range. Thinking about it, I eventually asked myself if these heterotrophic bacteria in your tanks, which supposedly outcompeted the competition when they had their metabolism boosted, only needed a temperature boost and not also a surplus of bacteria food to multiply.

The way I understand your situation, from what you described, is that there was a high potential for heterotrophic activity which was held back due to temperature and competition, is that it? Or is it much more complex than this with our invisible friends?

It should be simple enough for you to test a filter/no filter scenario, but I understand that might not be your priority right now.

 

[_Maq_]

@LMuhlen , you're basically targeting the question "what is the limiting factor for bacteria proliferation"? I'm asking the same question, and I can only guess.
We all know that food rots faster in higher temperature. That's why we have fridges. Obviously, it's not a lack of food (actually "substrate") at play here. However, lower temperature only hinders bacterial activity. In time, food rots in a fridge, too.
There's no external input of organic matter in my tanks - I do not feed any fish, only fertilize plants using mineral salts. Yet I believe there's some kind of permanent stock of food for microbes there, mostly in the substrate. Normally, there's a balance between bacterial consumption and the food available. Don't forget bacteria die ("lyse") within hours and turn back into food. But with temperature increase, bacteria "live faster" and proliferate. The balance is somehow lost.
I admit I'm struggling to comprehend these issues. But generally, our experience tells us that "stability" is a good thing. It seems that change in temperature can temporarily break this stability until it's established in new conditions. In the meantime, problems may occur.

 

[_Maq_]

It should be simple enough for you to test a filter/no filter scenario

Oh no, I think differently. It would require multiple tests, waiting for an opportunity, and I bet the results would be hard to interpret.
I have permanently some tests running for several years, and my experience tells that the results are too often surprising, ambiguous and permit multiple interpretation. Our tanks are very complex living systems, and we can measure only a few variables, while a plenty of others remain "hidden". Namely when we talk about microbes.

A few years ago I've run multiple tests on cycling newly established tanks and nitrification. The result was clear - any attempt to establish biological filtration was redundant; it did not make cycling any faster. (I could measure ammonia, nitrites, and nitrates quite reliably.) Since then, I quit (biological) filtration in my tanks. (It's cheaper.) Now, I admit that in certain situations biofilters might do some difference. Maybe. Possibly. Hard to prove.

 

[Andy Pierce]

A few years ago I've run multiple tests on cycling newly established tanks and nitrification. The result was clear - any attempt to establish biological filtration was redundant; it did not make cycling any faster.

Just so I'm clear on this, @_Maq_ there is no biological filtration (e.g. from a hang on the back filter system) in your tanks, but you DO still have water circulation right? For many people a "filter" is doing multiple things: actually filtering to remove particulates, providing a breeding environment for microbes, and circulating water in the tank. You think the "providing breeding environment for microbes" component isn't making a useful contribution, but how about the other pieces: removing particulates and water circulation?

 

[_Maq_]

You think the "providing breeding environment for microbes" component isn't making a useful contribution, but how about the other pieces: removing particulates and water circulation?

I'm definitely for water circulation, even oxygenation (venturi).
Removing particulates: I don't see larger particles as a big issue (in tanks where plants dominate over fish). Micro-particles, that's quite different thing. Sponges and ceramics can't remove them. This requires rather unorthodox filtration methods. I'm still on my way to find perfect solution. Diatom filter is the best but not handy, impractical.

 

[_Maq_]

Sorting out old pics, I chose to post a few of them here.

 

[_Maq_]

Branco, end-November

Cryptocoryne spiralis Tiger. Without issues, but it never grows any bigger. Long-term problem, no satisfactory answer. You can see, some leaves are greenish while others are coloured as intended. I've been observing this for a while and I believe it's iron which makes the difference.


Aponogeton madagascariensis. Holding well but somehow restricted, it's not the domineering plant I'm used to.


Ammannia is an interesting genus, and Ammannia pedicellata Gold perhaps most sensitive of them all. After long months of pitiful existence, the remnants revived and grow satisfactorily. But if you asked me what had made the trick, I'd have to admit I haven't the faintest idea. Ammannia remains mysterious to me, and therefore - very interesting.

 

[_Maq_]

Here is the mineralization / fertilization formula which I currently (several months) employ. It's the same for all Portugals. Note the formula 13 is standard, while 13.a is meant to push pH slightly down, and 13.b pushing pH slightly up.

 

[_Maq_]

Azul, end-November.


Cryptocoryne nurii between Lagenandra meeboldii Green and Cryptocoryne wendtii Rubella.


Lagenandra keralensis. A bit of a rarity. Slow grower. I've learnt it grows best in another tank of mine, in rather rough gravel and water very poor in nutrients.


Eriocaulon sp. Goiás. Quite hardy for an Eriocaulon. But how does it differ from Eriocaulon sp. Vietnam?


Echinodorus Reni. Perhaps as good as it gets in my conditions. Rotala wallichii used to be considered extremely demanding. It fits perfectly to my conditions, grows like a weed; I'm using it as a filler. On the right side, you can see Ammannia crassicaulis. This species grew poorly for a long time, now as if it got a new breath. This species probably never turns reddish, but its yellow-greenish leaves are no less beautiful.